I forgot to mention this earlier.
Last Thursday morning, I was waiting at Buffalo Lake, WI for UP 4014 to show up.
Pretty soon, that signature prop noise of a T-6 was heard and one came into view
from the NW. It followed the UP main close to where I was and then turned back
and repeated the maneuver, this time coming even closer. Someone else offered that
it was following the train. Sure 'nuff, it was and I'd bet that it was one of the participants
at nearby AirVenture in Oshkosh. Some pilot likely had interests in both aviation &
railroading.